Magnetic resonance imaging at 1.5 Tesla is safe in patients implanted with the Advisa MRI pacing system

21st February 2013

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Results of the Advisa MRI System clinical study have shown that scanning pacemaker patients in the 1.5 Tesla MRI environment is safe and effective with the Advisa MRI pulse generator and CapSure MRI 5086MRI lead system (Medtronic). The system allows MRI access without compromising positioning restrictions, including the cardiac region. Based on the clinical trial data, the new Advisa MRI system is now approved for use by the FDA.

Most MRI pacing systems have positioning restrictions for MRI scans or limitations of body parts scanned (particularly around the thoracic region). In the clinical trial, those restrictions and limitations were removed based on the strength of pre-clinical investigations of this new device, noted Gimbel et al. “Without the development of pacing systems capable of easily and safely undergoing chest scans without positioning restrictions, many patients with cardiovascular disease who would benefit most from MR scanning would be excluded,” the authors wrote.

This study sought confirmation of the safety and effectiveness of the Advisa MRI System during MRI scanning without positioning restrictions of the entire body. “This is the first completed prospective randomised evaluation of pacemaker patients receiving MRI scans within the cardiac region,” Gimbel et al wrote.

The researchers enrolled 263 patients with class I or II dual chamber pacemaker indications between June 2010 and October 2011. After successful device implant, the patients were randomised 2:1 to undergo 16 chest and head scans at 1.5 Tesla between 9−12 weeks post-implant (n=177) or not undergo MRI (n=86). The pacemaker system was evaluated immediately before, during and after MRI, one week and one month post-MRI, and similarly for the control group. The MRI scans were performed with 1.5 Tesla systems from GE Healthcare, Philips and Siemens.

In total, 150 patients had MRI scans, 148 of these patients were followed through the one- month post-MRI visit or later follow-up and were included in the analysis. None of the 148 patients reported MRI-related complications so the primary safety objective was met.In terms of effectiveness, the Advisa MRI System showed no evidence of pacing capture threshold changes, power-on-reset or unintended cardiac stimulation.

“Advisa MRI addresses all the risks of scanning pacemakers off-label such as power-on-reset, failure to pace (leaving the patient aystolic), rapid pacing, and battery depletion seen previously in a small percentage of patients during off-label scanning”, said Gimbel to Cardiac Rhythm News.

In the study, three deaths were reported¾two in the MRI group and one in the control group. None of these were related to the Advisa MRI System implant procedure, or MRI procedure, the authors noted.

When asked how this new system compares to devices currently available for use, Gimbel said: “This is a full featured device allowing rapid easy office management during device clinic and highly personalised programming for every patient’s need. When you combine this with a device that also has strong data supporting safe use while scanning any body part without positioning restrictions at 1.5 Tesla, you have got an unbeatable combination.”